Which Bilstein shock is best for my RV?

[dperkinstx]

I have a '94 28ft Minnie Winnie. I think it's more like 30ft bumper to bumper. I see Bilstein offers two shocks - the HD and the Comfort. They say the comfort is recommended for RV's under 30ft and the HDs are for over 30ft. I'm right on the cut-off line.

I'm new to RVing (bought it Jan, 2015). I have no idea how old the current shocks are. I feel like I get blown around a lot while driving. I don't want to buy the Comfort shocks just to find out I'm still getting blown around. I don't want to buy the HD shocks, then get bounced around because they're too stiff.

Any recommendations?

[pnichols]

tpi wrote:
Phil I will. It is E450. They're mail ordered and scheduled for install on the 22nd of June. I'll give two reports, a first impression and then a longer trip impression. I will pay particular attention to the slam from potholes and broken roads you mention. I do have the aftermarket sway bars with harder than stock bushings which also could contribute to harshness, but I will be able to at least give a before/after comparison.

Just dodged broken pavement on hwy 40 from Flagstaff to Needles. About half of it is in poor shape. Would be great comparison for ride but won't be there this summer.

I may beat you slightly with a Koni FSD installation on our 24 foot E450 Class C!

I just received a set for the rear yesterday and I'll try to get them installed this week. I'm going with just the rears first to see how well they tame the backend pounding on highway cracks. My truck service guy said no need to replace the OEM steering shock or OEM front socks anyway due to mileage, as it's too early yet. I have around 49,000 on it and so far have not noticed any front end road control or ride issues, so he may be right.

This is going to be a big week ... today we're picking up a couple of 115 amp hour Group 31 deep cycle 12 volt AGM batteries for the coach, too. 230 deep cycle amp hours tucked right under the step where they belong, so as to not reduce overall storage cabinet volume anywhere.

[pnichols]

My understanding of shocks is that they offer resistance to any up & down motion .... thus they dampen (shorten the duration of) bouncing you get from bare springs alone .... and they also resist the compression/extension you get in the opposing-side springs on road curves, when going over curbs, and from side-air-pressure pushes.

Given this, the last thing I want when going over highway cracks and pothole edges is any more opposition than absolutely necessary to the springs rapidly compressing and decompressing on each small vertical edge that the tire comes in contact with. Hence IMHO, one wants a soft (or no) shock action on highway cracks and pothole edges to eliminate the resulting jolts - so much as they come from the resistance of shocks. Of course the siffness of the springs is also felt as "jolts", too, on highway cracks and pothole edges - but lets not add to it with any resistance from the shocks. As I understand it, the Koni FSD shocks act as a very soft/weak shock during very rapid up & down motions ... which means little shock resistance (damping) is what you get with highway cracks and pothole edges.

Also IMHO, one of the best ways to add chassis stiffness on road curves, when going over curbs, and from side-air-pressure pushes is through use of sway bars, as now come stock on both the front and back of the Ford E350/E450 van chassis. I'm sure many other chassis under modern motorhomes now have both sway bars, too. Note, sway bars resist (but do not completely eliminate) the unequal compression/extension you get in the opposing-side springs on road curves, when going over curbs, and from side-air-pressure pushes. Sway bars do nothing to affect the straight up and down motion of the suspension when both sides of the vehicle move up and down the same amount at the same time - as in a bump or dip going all the way across the road surface. One can see this is how sway bars work by laying underneath your rig, studying the situation, and then putting two and two together.

I carry a full 80 lbs. of pressure in the rear LR E dually tires on our ~11,800 lb. E450 Class C. This is more pressure than is needed and doesn't NOT HELP with the jolting coming from the rear, but this maximum tire pressure offers other advantages ... so I'm relying on our Michelin 215/85R16 tires and our upcoming Koni FSD shocks in their rapid frequency mode ... to take some of the bite out of the jolts arising from highway cracks and pothole edges.

As an aside, at tire replacement time a few years ago I chose the 215/85 tire size specifically to put a taller and narrrower air chamber in between the steel rim and rough road surfaces. IMHO, today's wide low profile tires ride stiffer, and are best suited for high speed, high performance vehicles - not heavily loaded vehicles requiring high tire pressures but which one wants to still ride as soft as possible on the highway cracks and pothole edges all over the U.S..

[tpi]

I'm on short trip and zoned in on the stock Ford shocks and have some thoughts.

First off there is a curious mix of boulevard ride and impact harshness. In my motorhome most of the harshness comes from the rear axle.. hitting the same bump with front and rear ends-the rear impact is very significantly more noticeable. It is my view that significant amount of that impact is not related to shock absorbers at all. It is instead the big multi leaf packs with large amounts of internal friction. In other words if the shock absorbers were not there at all, there would be a lot of impact issues remaining. The best the shock can do is not add too much to this impact harshness.

Phil mentioned above that he thought the control to be sufficient. IMO I think it is in a normal range of control, but at the softer end. It is luxurious at lower speeds, but IMO flabby at high speed cornering. The control desired from shock absorbers is truly a matter of opinion.

To Phil: I think what you're looking for is aided by not carrying one PSI in the tires above what weight tables call for. I also think some tires may ride better than others and that would be worth exploring. I think most E rated tires are quite harsh. I'll certainly fill you in on whether the new FSDs control ride harshness significantly better than stock Ford. Certainly the front Ford suspension/shocks are transmitting very little harshness relative to the rear. I hope the FSDs control harshness better than stock Ford but have limited expectations.

[SCVJeff]

Koni- FSD

[tpi]

That would be perfect- a big knob you could turn to tighten up control as needed. Today I was driving on suburban roads at 45 MPH and the control of the stock shocks were entirely adequate. In fact there would be nothing that would even hint a change was necessary except some rocking entering streets or driveways-which alone wasn't a big deal.

Not some automatic system either-complete manual adjustment..55-60 mph sweeping corners on good roads--crank her down...

[ron_dittmer]

Our old 1983 Toyota chassis motor home of yesteryear had driver-adjustable air bags. With regards to harshness of ride, the less air the softer the ride. The more air, the stiffer the ride. 15 psi was the recommended minimum as not to damage the air bags. I would run with 15 psi when conditions were ideal for driving, but cross-winds and mountain driving, I would put in 60 psi to improve handling at the sacrifice of a softer ride.

Regarding shock absorbers, I owned a 2003 Corvette with adjustable shocks. They were the current-day technology adjustable magnetic ride shocks which had a two position setting, Touring and Performance. Touring was a soft setting with a comfortable ride and normal handling. Performance was a stiff hard (heavy duty) setting which made the car handle better yet as long as the road surface was real smooth. The "Performance" setting offered a rough ride on the roads I commuted on so I never used it except to "toy" with.

I wonder if the Koni-FSD shocks would be like my Corvette, but with an automated two position setting offering a smoother ride under good motionless-suspension conditions, but then kicks into instantaneous heavy duty mode when the rig's supension starts to move.....hence I wonder if there is reduced vibration of which I previously mentioned in a prior reply on this subject matter here.

ron.dittmer wrote:
I had read up on FSDs years ago and recall inside they have a mechanical limiting check valve that allows hydraulic fluid to pass thru to make the shocks soft under normal conditions, but kick into heavy duty mode on demand. The end result is that you get a soft ride except when road conditions change which require heavy duty shocks.

I have the other Koni RV shocks, the red colored adjustable model. They are set highest, so I would imagine they are comparable to the HD Bilsteins. As an experiment with my wife driving, I laid on my back on the floor over the rear axle. There really is a lot of road vibration felt there laying on the floor. It would be great if the FSDs can reduce that. It sounds like that is what they are designed to do. A soft and heavy duty shock, all in one.

Here was the air bag controller above the driver's left knee in my old 1983 Toyota motor home.


Here was the two position shock adjuster in my 2003 Corvette, just to the left of the parking brake lever.

[OFDPOS]

Someone correct me if I'm wrong here.
A shock absorber on an automobile does one thing and one thing only, keeps the car from bouncing.
So just how are shocks going to help with the jar of the crack joints /potholes in the road ? Shocks mainly control the bounce up and down once you hit the uneven pavement. They don't carry the burden of the weight , the leaf springs do. So wouldn't reworking the leaf springs help with the jar?

I've never been in nor used a truck with air bags installed on the back, But wouldn't a set of airbags help take some weight of the rear springs giving them more room to travel to lesson the harshness of the pothole / crack joint in the road , along with better shocks to help with the bounce after effect ?

It seems or at least every Ford chassis MH we test drove every single one slammed hard on any little dip and cracks/joints on the freeway.
I'm for thinking the rear leaf springs are pretty much maxed out to begin with then after time just get worse. Now add all the stuff we put in them ! Yeah we all know about CCC etc , but...

If I had a Ford chassis MH and money to try stuff ,I'd try a set of airbags on the rear and test different air pressures with getting some weight off the leaf springs and seeing how much that would help with the sudden jars of the potholes , crack/joints.
Yes,,, shocks will help with sway , jars ,Key word HELP (not cure) but their main purpose is to control the bounce up and down AFTER you hit the ?

[SCVJeff]

That'll be an interesting report.
Mine is obviously significantly heavier and harder to control because of that, but I didn't notice any additional stiffness really at all. That was my concern too.

[tpi]

Phil I will. It is E450. They're mail ordered and scheduled for install on the 22nd of June. I'll give two reports, a first impression and then a longer trip impression. I will pay particular attention to the slam from potholes and broken roads you mention. I do have the aftermarket sway bars with harder than stock bushings which also could contribute to harshness, but I will be able to at least give a before/after comparison.

Just dodged broken pavement on hwy 40 from Flagstaff to Needles. About half of it is in poor shape. Would be great comparison for ride but won't be there this summer.

[pnichols]

Not related to the OP's Bilstein inquiry, but ... I'll probably be putting Koni FSD's on our 24 foot Itasca E450 Class C this summer before a long trip across the U.S..

Our stock Ford shocks (~49K miles on them) - along with the stock front & back sway bars and steering control shock - have always kept the side-sway and steering under control just fine. I do not experience any underdamping at high speeds, that I'm aware of - including in 50-60 MPH cross-wind gusts on the highway. What the stock Ford shocks didn't ever, and don't, do is soften the sharp jolts from highway cracks and pothole edges. This is the terrible stuff we experience in the right-hand truck lanes on highways and freeways all over the U.S. ... which is where we like to cruise at speeds under 60 MPH. I feel that a soft shock for the cracks and pothole edges and a stiff shock for everything else is what's needed. The explanation of operation on the Koni FSD shocks sounds like both situations are exactly what their FSD shock technology is supposed to address in one shock. What I DON'T WANT is a stiffer shock full-time anywhere on our Class C, so if I were to go the Bilstein route it would be the comfort version.

Tom ... please let us know what you think as soon as you have some run-time on your FSDs ... I'm anxiously awaiting your report! P.S. Is your Lazy Daze built on an E350 or E450 chassis?

[quingus]

When I drove my C off the lot, man it was all over. Freeway driving forget about it. I came to this forum, did my homework and this what I ended up doing. Koni's all around. Front and Rear sway bars (roadmasters). Safe T Steer, stabilizer. Installed myself. Front Koni driver side was a b****. Oh yeah all new set of tread at proper weight. 65lb front 80lb rear. Talk about a difference. I have a 30' Fleetwood Jamboree Sport 07'. That info says long and heavy. Def get an alignment, but shocks are needed. Anything is better than anything stock on that Ford chassis. Except engine an transmission. All of course IMHO.

[tpi]

In theory the FSD sounded appealing..if the compression damping could be made stiffer due to the variable valving, then it could indeed control the rocking and swaying better. I believe these vehicles are prone to self steer due to roll and rocking..anything to reduce that would translate to better handling. Also like other vehicles I've had with weak shocks, the motorhome became floaty and underdamped at high speeds. As Buick used to say in their 1950s ads, "buoyant." Which is probably fine on the boulevard at 35 MPH.

[ron_dittmer]

tpi wrote:
I ordered four of the Koni FSD shocks. At the price a leap of faith.. But I've already spent plenty on the suspension, love the motorhome in general, and I'm certain they'll have more control vs. the Ford OEM (which I found lacking from day 1). Whether or not they work better for me than the Bilstein would is the loaded question. Anyway late in June when they're installed I'll give a report. No expectations of sedan ride and handling but I do expect improvement.

I look forward to your evaluation/report.

[tpi]

I ordered four of the Koni FSD shocks. At the price a leap of faith.. But I've already spent plenty on the suspension, love the motorhome in general, and I'm certain they'll have more control vs. the Ford OEM (which I found lacking from day 1). Whether or not they work better for me than the Bilstein would is the loaded question. Anyway late in June when they're installed I'll give a report. No expectations of sedan ride and handling but I do expect improvement.